[PATCH] gcc: xtensa: reorder movsi_internal patterns for better code generation during LRA

[PATCH] gcc: xtensa: reorder movsi_internal patterns for better code generation during LRA

[Max Filippov]

After switching to LRA xtensa backend generates the following code for
saving/loading registers:

    movi     a9, 0x190
    add      a9, a9, sp
    s32i.n   a3, a9, 0

instead of the shorter and more efficient

    s32i     a3, a9, 0x190

E.g. the following code can be used to reproduce it:

    int f1(int a, int b, int c, int d, int e, int f, int *p);
    int f2(int a, int b, int c, int d, int e, int f, int *p);
    int f3(int a, int b, int c, int d, int e, int f, int *p);

    int foo(int a, int b, int c, int d, int e, int f)
    {
        int g[100];
        return
            f1(a, b, c, d, e, f, g) +
            f2(a, b, c, d, e, f, g) +
            f3(a, b, c, d, e, f, g);
    }

This happens in the LRA pass because s32i.n and l32i.n are listed before
the s32i and l32i in the movsi_internal pattern and alternative
consideration loop stops early.

gcc/

	* config/xtensa/xtensa.md (movsi_internal): Move l32i and s32i
	patterns ahead of the l32i.n and s32i.n.
---
 gcc/config/xtensa/xtensa.md | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/gcc/config/xtensa/xtensa.md b/gcc/config/xtensa/xtensa.md
index 1a2249b059a0..5cdf4dffe700 100644
--- a/gcc/config/xtensa/xtensa.md
+++ b/gcc/config/xtensa/xtensa.md
@@ -1270,13 +1270,15 @@
 })
 
 (define_insn "movsi_internal"
-  [(set (match_operand:SI 0 "nonimmed_operand" "=D,D,D,D,R,R,a,q,a,a,W,a,a,U,*a,*A")
-	(match_operand:SI 1 "move_operand" "M,D,d,R,D,d,r,r,I,Y,i,T,U,r,*A,*r"))]
+  [(set (match_operand:SI 0 "nonimmed_operand" "=D,D,D,a,U,D,R,R,a,q,a,a,W,a,*a,*A")
+	(match_operand:SI 1 "move_operand" "M,D,d,U,r,R,D,d,r,r,I,Y,i,T,*A,*r"))]
   "xtensa_valid_move (SImode, operands)"
   "@
    movi.n\t%0, %x1
    mov.n\t%0, %1
    mov.n\t%0, %1
+   %v1l32i\t%0, %1
+   %v0s32i\t%1, %0
    %v1l32i.n\t%0, %1
    %v0s32i.n\t%1, %0
    %v0s32i.n\t%1, %0
@@ -1286,13 +1288,11 @@
    movi\t%0, %1
    const16\t%0, %t1\;const16\t%0, %b1
    %v1l32r\t%0, %1
-   %v1l32i\t%0, %1
-   %v0s32i\t%1, %0
    rsr\t%0, ACCLO
    wsr\t%1, ACCLO"
-  [(set_attr "type"	"move,move,move,load,store,store,move,move,move,move,move,load,load,store,rsr,wsr")
+  [(set_attr "type"	"move,move,move,load,store,load,store,store,move,move,move,move,move,load,rsr,wsr")
    (set_attr "mode"	"SI")
-   (set_attr "length"	"2,2,2,2,2,2,3,3,3,3,6,3,3,3,3,3")])
+   (set_attr "length"	"2,2,2,3,3,2,2,2,3,3,3,3,6,3,3,3")])
 
 (define_split
   [(set (match_operand:SHI 0 "register_operand")
-- 
2.39.2